intestinal disease and, in both cases, the cysts must be ingested 

 to contract disease. Of importance concerning the risk to 

 divers, cysts of E, histolytica can survive municipal chlorine 

 levels, temperatures of 0°C for several weeks and temperatures 

 close to 30°C for up to three days (Albach and Booden, 1978). 

 They are, therefore, hardy organisms which persist in the 

 environment and may pose a problem if ingested by a diver, 

 especially via splashback through the regulator. E. histolytica 

 and G. lamblia exposure would be most likely to occur in areas 

 where sewage effluent enters because of the intestinal habitat of 

 these protozoans. 



Actinomycetes 



Actinomycetes are branched, spore-forming bacteria with 

 elongated mycelia. They are found in the upper layers of soil, 

 but have also been isolated from freshwater (Al-Diwany and Cross, 

 1978) and from estuarine (Walker and Colwell, 1975) and marine 

 (Weyland, 1969) environments. Most actinomycetes in aquatic 

 habitats are allochthonous organisms washed in with land runoff 

 (Al-Diwany and Cross, 1978). The spores are deposited eventually 

 into the sediment (Cross and Johnson, 1971) and, thereby, 

 Actinomycetes become especially abundant in sediments. These 

 organisms may also be associated with sewage effluent 

 (Lechevalier and Lechevalier, 1974), and with coastal dredge 

 material dumped at sea (Attwell et al., 1981). Actinomycetes 

 species may be obligate pathogens, e.g., Mycobacterium 

 tuberculosis or M. leprea ; or they may be opportunists, e.g. 

 Arachnia and Actinomyces spp. However, Actinomycete infections 

 acquired from contact with natural waters are likely to be caused 

 by members of the genus Nocardia , Actinomadura or Streptomyces 

 (Pulverer and Schaal, 1978). 



Nocardia enter the body through wounds or via inhalation and 

 may result in systemic or pulmonary nocardiosis. Actinomadura 

 and Streptomyces may enter through skin lesions and give rise to 

 actinomycetoma. The best protection for divers against an 

 Actinomycete infection is to wear protective suits when working 

 in polluted waters and to avoid disturbing the sediment when 

 working near the bottom, since spores of these organisms are 

 prevalent in the sediment. 



Anaerobes 



The significance of obligate anaerobes in disease of divers 

 has not been studied as thoroughly as has that of the 

 facultatively anaerobic bacteria. However, Bacteroides and 

 Clostridium sp. are potentially pathogenic for humans. 

 Therefore, if present in polluted waters, they can present a risk 

 to divers. Daily et al . (1979 and 1981c) collected samples from 

 the New York Bight and Anacostia River to determine if obligate 

 anaerobes were present in sufficiently large numbers to represent 



324 



